There will never be an asic sold for less than the manufacturer can make it for.
Not sure I understand your point. Running costs are a separate issue from manufacturing costs.
First of all running costs for AM is likely less than running costs for home miners because of the price of electricity and the high efficiency.
Second, when manufacturers can make asics for half the cost that the average joe can get one for that means they can easily have twice the hashing power for the same cost.
We know that just about every asic available right now will either just barely or not reach ROI but asic manufacturers will have no problem reaching ROI.